Emergency crews had to wait 16 hours while the Braintree water tank was drained Thursday before they could recover the body of a man who had died while performing inspection work inside the massive structure, WCVB reported.

One million gallons of icy water had to be removed from the municipal tank in order to pull the body out.

The man, identified as David Scott, was a diver who was performing routine maintenance work inside the Lincoln Street tank when he reported a problem with his equipment at about 10 a.m. Thursday, and he began to lose air.

The tank is one of five that supplies drinking water to Braintree. Scott, who worked for Pittsburg Tank & Tower, was performing the inspection as part of maintenance that takes place every five years, according to WCVB.

"This latest loss again reminds us that more advocacy is needed to protect workers," said Al Vega, interim executive director of the Massachusetts Coalition for Occupational Safety & Health, the advocacy group. It scheduled Tuesday's candlelight vigil, in which families of other workers who have been killed on the job will speak. The coalition will also call on lawmakers to pass pending bills aimed at improving worker safety regulations.